Add Calendar integration (read-only)

diary.go

@@ -533,6 +533,8 @@ type diarySection struct {
 	EditURL string        // year-file section edit URL ("" = no edit button)
 	Body    template.HTML // rendered markdown body (excludes the heading line)
 	Photos  []diaryPhoto
+	Events  string // day's calendar events, comma-separated (level 3 only)
+	Weight  string // day's weight from the weight calendar (level 3 only)
 }
 
 type diaryContentData struct {
@@ -623,6 +625,7 @@ func renderDiaryYear(yearFS, yearURL string) template.HTML {
 
 	out := buildFileSections(sections, photos, yearURL)
 	out = appendVirtualEntries(out, sections, photos, year, yearURL)
+	attachCalendarLines(out, year)
 	return renderDiaryContent(out)
 }
 
@@ -746,6 +749,28 @@ func appendVirtualEntries(existing []diarySection, sections [][]byte, photos []d
 	return out
 }
 
+// attachCalendarLines fills the events and weight lines of every day section
+// (real or virtual) from the calendars' diary and weight roles.
+func attachCalendarLines(sections []diarySection, year int) {
+	lines := calendarDayLines(
+		time.Date(year, time.January, 1, 0, 0, 0, 0, time.Local),
+		time.Date(year+1, time.January, 1, 0, 0, 0, 0, time.Local))
+	if len(lines) == 0 {
+		return
+	}
+	for i := range sections {
+		s := &sections[i]
+		if s.Level != 3 {
+			continue
+		}
+		if _, _, _, ok := parseISODate(s.ID); !ok {
+			continue
+		}
+		l := lines[s.ID[:10]]
+		s.Events, s.Weight = l.Events, l.Weight
+	}
+}
+
 // isRealDateSection reports whether a rendered diarySection is one of the
 // date-headed slots (`## YYYY-MM` or `### YYYY-MM-DD`) the virtual-entry
 // interleave sorts against.